The focus of our research is on renin control and arterial pressure regulation, particularly as these relate to renal function and the hypertensive state. Cardiovascular and renin responses to Central Nervous (CNS) electrical stimulation are being studied in free-running dogs by telemetry techniques. We will observe mechanisms underlying both short-term responses and long-term adaptive processes during prolonged enhancement of CNS drive. In addition, hormonal and renal disturbances are to be superimposed on the enhanced CNS drive to test the idea that other predisposing factors when combined with central nervous disturbances may lead to sustained hypertension even though, individually, these factors fail to support the disease. In other studies we are observing sensory and cellular mechanisms responsible for renin release during elevated arterial PCO2. In yet other studies we are examining mechanisms whereby intrarenal prostaglandins and/or their precursors and metabolites influence renin in release in normal and hypertensive models. Particular attention will be focused on a possible Ca ions involvement in fundamental renin secretory processes.